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Publications

Publications by Carla Queirós

2023

Targeted intervention to achieve waste reduction in gastrointestinal endoscopy

Authors
Neves, JAC; Roseira, J; Queirós, P; Sousa, HT; Pellino, G; Cunha, MF;

Publication
GUT

Abstract
Objective Endoscopy is healthcare's third largest generator of medical waste in hospitals. This prospective study aimed to measure a single unit's waste carbon footprint and perform a pioneer intervention towards a more sustainable endoscopy practice. The relation of regulated medical waste (RMW; material fully contaminated with blood or body fluids or containing infectious agents) versus landfill waste (non-recyclable material not fully contaminated) may play a critical role. Design In a four-stage prospective study, following a 4-week observational audit with daily weighing of both waste types (stage 1), stage 2 consisted of a 1-week intervention with team education of waste handling. Recycling bins were placed in endoscopy rooms, landfill and RMW bins were relocated. During stages 3 (1 month after intervention) and 4 (4 months after intervention), daily endoscopic waste was weighed. Equivalence of 1 kg of landfill waste to 1 kg carbon dioxide equivalent (CO2e) and 1 kg of RMW to 3kgCO(2e) was assumed. Paired samples t-tests for comparisons. Results From stage 1 to stage 3, mean total waste and RMW were reduced by 12.9% (p=0.155) and 41.4% (p=0.010), respectively, whereas landfill (p=0.059) and recycling waste increased (paper: p=0.001; plastic: p=0.007). While mean endoscopy load was similar (46.2 vs 44.5, p=0.275), a total decrease of CO2e by 31.6% (138.8kgCO(2e)) was found (mean kgCO(2e)109.7 vs 74.9, p=0.018). The annual reduction was calculated at 1665.6kgCO(2e). All these effects were sustained 4 months after the intervention (stage 4) without objections by responsible endoscopy personnel. Conclusion In this interventional study, applying sustainability measures to a real-world scenario, RMW reduction and daily recycling were achieved and sustained over time, without compromising endoscopy productivity.

2022

MOF-Based Materials with Sensing Potential: Pyrrolidine-Fused Chlorin at UiO-66(Hf) for Enhanced NO2 Detection

Authors
Queiros, C; Moscoso, FG; Almeida, J; Silva, AMG; Sousaraei, A; Cabanillas-Gonzalez, J; Carrott, MR; Lopes-Costa, T; Pedrosa, JM; Cunha-Silva, L;

Publication
CHEMOSENSORS

Abstract
An efficient strategy to develop porous materials with potential for NO2 sensing was based in the preparation of a metal-organic framework (MOF), UiO-66(Hf), modified with a very small amount of meso-tetrakis(4-carboxyphenyl) N-methylpyrrolidine-fused chlorin (TCPC), TCPC@MOF. Chlorin's incorporation into the UiO-66(Hf) framework was verified by several characterization methods and revealed that the as-synthesized TCPC@MOF brings together the chemical stability of UiO-66(Hf) and the photophysical properties of the pyrrolidine-fused chlorin which is about five times more emissive than the porphyrin counterpart. TCPC@MOF was further incorporated into polydimethylsiloxane (PDMS) and the resulting TCPC@MOF@PDMS film was tested in NO2 gas sensing. It showed notable sensitivity as well as a fast response in the range between 0.5 and 500 ppm where an emission intensity quenching is observed up to 96% for 500 ppm. This is a rare example of a chlorin-derivative used for gas-sensing applications through emission changes, and an unusual case of this type of optical-sensing composites of NO2.

2018

Fluorescent Rosamine/TiO2 Composite Films for the Optical Detection of NO2

Authors
Guillen, MG; Suarez, B; Roales, J; Gamez, F; Vargas, AP; Moscoso, FG; Lopes Costa, T; Queiros, C; Silva, AMG; Pedrosa, JM;

Publication
JOURNAL OF SENSORS

Abstract
Two rosamine derivatives were used as fluorescent sensors for the detection of NO2, a toxic and oxidant gas whose presence in populated areas needs to be controlled. Both compounds shared the same molecular structure but had different peripheral substituents: a carboxylic acid and an amino group. Transparent nanocrystalline TiO2 films were prepared by screen printing and used as substrates, where the rosamines were incorporated by simple immersion into their respective solutions to form composite films. According to the molecular structures of the rosamines, the anchoring to the substrates was proposed to be by either covalent bonding and electrostatic interaction, or only electrostatic interaction, and was determined by the different substituents in each rosamine. Upon their exposure to increasing concentrations of NO2, both types of composite films showed intense and fast spectral changes, and the speed of response was related to the concentration of the gas. The anchoring mode and the electrophilic effect of the substituents determined the better sensing capability and the faster response shown by the carboxylic derivative in all cases.

2020

From Discrete Complexes to Metal-Organic Layered Materials: Remarkable Hydrogen Bonding Frameworks

Authors
Queiros, C; Silva, AMG; de Castro, B; Cunha Silva, L;

Publication
MOLECULES

Abstract
A series of metal-organic coordination complexes based on alkaline-earth metal centers [Mg(II), Ca(II), and Ba(II)] and the ligand 5-aminoisophthalate (aip(2-)) revealed notable structural diversity, both in the materials' dimensionality and in their hydrogen bonding networks: [Mg(H2O)(6)].[Mg-2(Haip)(H2O)(10)].(Haip).3(aip).10(H2O) (1) and [Mg(aip)(phen)(H2O)(2)].(H2O) (2) were isolated as discrete complexes (0D); [Ca(aip)(H2O)(2)].(H2O) (3), [Ca(aip)(phen)(H2O)(2)].(phen).(H2O) (4), and [Ba-2(aip)(2)(phen)(2)(H2O)(7)].2(phen).2(H2O) (5) revealed metal-organic chain (1D) structures, while the [Ba(aip)(H2O)] (6) showed a metal-organic layered (2D) arrangement. Furthermore, most of these metal-organic coordination materials revealed interesting thermal stability properties, being stable at temperatures up to 450 degrees C.

2021

Multidimensional Ln-Aminophthalate Photoluminescent Coordination Polymers

Authors
Queiros, C; Sun, C; Silva, AMG; de Castro, B; Cabanillas Gonzalez, J; Cunha Silva, L;

Publication
MATERIALS

Abstract
The development of straightforward reproducible methods for the preparation of new photoluminescent coordination polymers (CPs) is an important goal in luminescence and chemical sensing fields. Isophthalic acid derivatives have been reported for a wide range of applications, and in addition to their relatively low cost, have encouraged its use in the preparation of novel lanthanide-based coordination polymers (LnCPs). Considering that the photoluminescent properties of these CPs are highly dependent on the existence of water molecules in the crystal structure, our research efforts are now focused on the preparation of CP with the lowest water content possible, while considering a green chemistry approach. One- and two-dimensional (1D and 2D) LnCPs were prepared from 5-aminoisophthalic acid and Sm3+/Tb3+ using hydrothermal and/or microwave-assisted synthesis. The unprecedented LnCPs were characterized by single-crystal X-ray diffraction (SCRXD), powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM), and their photoluminescence (PL) properties were studied in the solid state, at room temperature, using the CPs as powders and encapsulated in poly(methyl methacrylate (PMMA) films, envisaging the potential preparation of devices for sensing. The materials revealed interesting PL properties that depend on the dimensionality, metal ion, co-ligand used and water content.

2022

Biogenic Amine Sensing Based on Rosamine a N-Methylpyridinium Derivative Supported on Silica Materials from Rice Husk

Authors
Queiros, C; Ribeiro, SO; Silva, AMG; Leite, A;

Publication
SENSORS

Abstract
In this work new rosamine-silica composites were prepared and their sensing ability towards different amines was assessed. Rice husk wastes were used as a biogenic silica source. Silica was extracted by thermal treatment, before rice husk ash and after acid leaching with citric acid-treated rice husk ash. Mesoporous material (SBA-15) was also prepared using the extracted silica. The prepared materials were characterized by several techniques such as FTIR, XRD, SEM and N-2 adsorption. The materials were then used as adsorbents of the chromophore N-methylpyridinium rosamine (Ros4PyMe). The obtained loaded composites were tested in solution for amines sensing (n-butylamine, aniline, putrescine and cadaverine). The detection studies were analyzed by fluorescence and revealed 40% and 48% quenching in fluorescence intensity for the composite Ros4PyMe@SBA in the presence of the biogenic amines cadaverine and putrescine, respectively. The composite was also sensitive in the powder form, changing the color from violet to pale pink in the presence of putrescine vapors with a fast response (around 2 min), the process being reversible by exposure to air.

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